From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753395AbbAEMiR (ORCPT ); Mon, 5 Jan 2015 07:38:17 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:44022 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753135AbbAEMiQ (ORCPT ); Mon, 5 Jan 2015 07:38:16 -0500 From: Wang Nan To: , , CC: , , Subject: [PATCH] kprobes: bugfix: force unoptimize when disable kprobes. Date: Mon, 5 Jan 2015 20:32:20 +0800 Message-ID: <1420461140-27153-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020204.50F2CDBD.0090,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: c5b0f7242290f3cd7460b973d5ddb2d9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Original code failed to disarm the probed instruction after echo 0 > /sys/kernel/debug/kprobes/enabled if OPTPROBE is enabled. This is caused by a piece of logically inconsistent code: unoptimize_kprobe(p, false); if (!kprobe_queued(p)) { ... } unoptimize_kprobe() with 'force' == false queues p onto unoptimizing_list, so following kprobe_queued() check always fail unless another core schedules optimizer and does the unoptimization very soon. This logic causes arch_disarm_kprobe() failed to get execute, lefts a breakpoint at the probed address, instead of restoring it. This patch uses force unoptimize instead. Signed-off-by: Wang Nan --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b185464..9fbe0c3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -869,7 +869,7 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) { struct kprobe *_p; - unoptimize_kprobe(p, false); /* Try to unoptimize */ + unoptimize_kprobe(p, true); /* Try to unoptimize */ if (!kprobe_queued(p)) { arch_disarm_kprobe(p); -- 1.8.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: wangnan0@huawei.com (Wang Nan) Date: Mon, 5 Jan 2015 20:32:20 +0800 Subject: [PATCH] kprobes: bugfix: force unoptimize when disable kprobes. Message-ID: <1420461140-27153-1-git-send-email-wangnan0@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Original code failed to disarm the probed instruction after echo 0 > /sys/kernel/debug/kprobes/enabled if OPTPROBE is enabled. This is caused by a piece of logically inconsistent code: unoptimize_kprobe(p, false); if (!kprobe_queued(p)) { ... } unoptimize_kprobe() with 'force' == false queues p onto unoptimizing_list, so following kprobe_queued() check always fail unless another core schedules optimizer and does the unoptimization very soon. This logic causes arch_disarm_kprobe() failed to get execute, lefts a breakpoint at the probed address, instead of restoring it. This patch uses force unoptimize instead. Signed-off-by: Wang Nan --- kernel/kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b185464..9fbe0c3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -869,7 +869,7 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt) { struct kprobe *_p; - unoptimize_kprobe(p, false); /* Try to unoptimize */ + unoptimize_kprobe(p, true); /* Try to unoptimize */ if (!kprobe_queued(p)) { arch_disarm_kprobe(p); -- 1.8.4